The Martin County Sheriff's Office is investigating the deaths of two children as a possible drowning in Jensen Beach.
It happened Friday evening in the Pinecrest Lakes community.
Investigators said a 7-year-old boy and a 9-year-old girl were left alone in a swimming pool with the homeowner's scuba tank that was placed into the water.
The sheriff's office said the adults walked away from the pool area for a short amount of time to look at another piece of diving equipment. The adults returned and found the children and the dive tank at the bottom of the pool. The adults pulled the kids from the pool and tried CPR before rescue crews arrived.
The children died Tuesday morning.
A parent told investigators the siblings were experienced swimmers and proficient divers and had been at the home before to use the pool and scuba equipment The children were visiting from a neighboring county, the sheriff's office said.
The medical examiner will determine a cause of death. The sheriff's office says it's working with the State Attorney's Office to investigate the circumstances of the deaths, including potential issues with the dive equipment used by the children.